Radiation absorbing metal pipe

ABSTRACT

The invention relates to the field of solar energy usage and, particularly, to solar systems, which operate on the base of concentration of direct solar radiation. The invention proposes a radiation absorbing metal pipe intended for heating gaseous medium or gaseous-liquid mixture. 
     The proposed radiation absorbing metal pipe is constructed from perforated plates. These plates are provided with inclined or two-stage upright rims. The plates are stacked and sealingly joined with formation of a tubular unit. 
     Such tubular units with absorbing coatings of their external surfaces can be applied in following solar thermal systems: parabolic trough collectors; solar thermal collectors with usage of linear Fresnel reflectors; for a system with an array of tracking mirrors and a central receiver mounted on a tower or on the ground.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable

FIELD OF THE INVENTION

This invention relates to a field of solar energy usage and,particularly, to solar systems, which operate on the base ofconcentration of direct solar radiation. In addition, the invention canbe used for superheating steam in thermal power plants.

BACKGROUND OF THE INVENTION

This invention relates to a field of solar energy usage and,particularly, to solar systems, which operate on the base ofconcentration of direct solar radiation.

The solar systems may be used as a source of thermal energy in powerplants, or as a source of thermal energy for carrying outthermo-chemical processes.

There are three main types of the solar concentrating systems, which mayput into practice the proposed invention:

1. Parabolic trough collectors (PTCs);2. Solar thermal collectors with application of linear Fresnelreflectors (LFRs).3. An array of flat or slightly concave mirrors, or heliostats, which isused to reflect their incident direct solar radiation onto a centralreceiver mounted on a tower (STP) or on the ground.

PTCs can effectively produce heat at temperatures between 50° C. and400° C. Concentrating mirrors of PTCs are made by bending sheets ofreflective material into a parabolic shape (a trough shape). A receiveris designed as a metal tube with a radiation absorbing coating on itsexternal surface; the metal tube is arranged in a glass tube with theevacuated space between this metal tube and the glass tube.

The receiver is placed along the focal line of the parabolic mirrors.

When the parabolic trough-wise reflector is pointed towards the sun,parallel rays incident on the parabolic trough-wise reflector arereflected onto the receiver tube. It is sufficient to use a single axistracking of the sun and thus long collector modules are produced. Thecollector can be orientated in an east-west direction, tracking the sunfrom north to south, or orientated in a north-south direction andtracking the sun from east to west.

LFR technology relies on an array of linear mirror strips whichconcentrate light onto a fixed receiver mounted on a supportingconstruction. Concentrated radiation receivers have a same design as inthe case of the PTCs.

It is widely recognized that application of concentrating solarcollectors with direct steam generation (DSG) instead of heating thermaloil allows significant diminishment of electricity generation cost inthe concentrating solar power plants and, at the same time, to achievehigher efficiency.

Detailed discussion regarding solar power plant with direct steamgeneration is presented in an article: J. Birnbaum et al. “A Concept forFuture Parabolic Trough Based Solar Thermal Power Plant”,PREPRINT-ICPWSXV, Berlin, Sep. 8-1, 2008.

For extremely high inputs of radiant energy, an array of flat orslightly concave mirrors, or heliostats, is used to reflect theirincident direct solar radiation onto a central receiver mounted on atower or on the ground. In such a way, this combination of the trackingmirrors and the central receiver serves as a source of thermal energy inthe solar tower power plant (STP).

The concentrated solar radiation absorbed by the central receiver istransferred into thermal energy of a circulating heat transfer medium.

The solar concentrating system, which includes the heliostat achieveconcentration ratios of 300-1500 and so are highly field, may efficientboth at collecting energy and at converting it to electricity.

There are two technical problems in operation of the receivers of thePTC, LFR and STP systems.

Uneven heating of radiation absorbing pipes in their circumferentialdirection by concentrated radiation and, as result, their deformation.

This deformation is expressed in bending the radiation absorbing pipesout of their position in the focal areas and diminishment of theirefficiency. In addition, it can cause mechanical failure of thereceiver, especially, for PTC and LFR systems.

An additional technical problem for PTC, LFR and STP systems isrelatively low values of heat transfer coefficients for gaseous heattransfer medium flowing in the radiation absorbing pipes.

It requires operation with high temperature drops between the outersurfaces of the radiation absorbing pipes and the gaseous heat transfermedium. This causes elevation of heat losses mainly by thermal radiationand, in turn, diminishes additionally efficiency of PTC, LFR and STPsystems, when they are used for superheating steam, heating thepressurized air or heating a gaseous medium for execution ofthermo-chemical reactions.

There are some patents and patent applications intended to solve theseproblems.

A solar fluid heater device is disclosed in U.S. Pat. No. 1,575,309 toAnderson. The efficiency of heat transfer is enhanced in this device byuse of heat transfer baffles disposed within a fluid conveying pipe andextending longitudinally thereof.

U.S. Pat. No. 4,026,273 describes a trough-concentrating system with aradiation absorbing pipe with a plurality of convective heat transferfins within the radiation absorbing pipe; these heat transfer fins arearranged longitudinally.

However, the longitudinal heat transfer fins cannot enhance the internalsurface of the radiation absorbing pipe in fife-to-one ratio or moreand, at the same time, to increase significantly the heat transfercoefficient for the fins themselves as for pin-wise fins. At the sametime such enhanced heat transfer is required for the radiation absorbingpipe in PTC, LFR and STP systems.

U.S. Pat. No. 5,460,163 discloses a trough-shaped solar radiationcollector intended for steam generation. A trough-shaped mirrorextending in a longitudinal direction receives and reflects radiationonto an absorber line enclosing within its interior a steam generatortube in which water is heated, vaporized and superheated. Heat istransferred transversely from the absorber line to the steam generatortube by heat pipe segments spaced longitudinally along the absorberline.

It is clear, that this technical solution does not solve the problem oflow values of the heat transfer coefficient for heat transfer from theinternal surface of the steam generator tube, when the generatedsaturated steam to be superheated.

WO 2011101485 describes a solar heat receiver tube for direct steamgeneration, comprising at least one outer absorber tube with an internalabsorber tube space and at least one inner water tube with an internalwater tube space for carrying water. The inner water tube is arranged inthe internal absorber tube space. The outer absorber tube and the innerwater tube are formed and arranged such that solar energy can beabsorbed by the outer absorber tube and absorbed solar energy can betransferred from the outer absorber tube to the inner water tube for thesteam generation within the internal water tube space. Inside the watertube liquid water can be transformed into vaporous water.

This technical solution is analogical to U.S. Pat. No. 5,460,163.

U.S. Pat. No. 5,465,708 describes a trough-shaped collector with anabsorber pipe member; this absorber pipe member has an interior with avaporizer tube having an essentially round cross section, which extendsin the interior of the absorber pipe member for transporting heat in thelongitudinal direction, and the vaporizer tube is thermally coupled tothe absorber pipe member via a heat transport medium presented betweenthe vaporizer tube and the absorber screen for transporting heattransversely to the longitudinal direction.

This technical solution is analogical to U.S. Pat. No. 5,460,163.

U.S. Pat. No. 5,860,414 (DE 43 31 784) discloses a trough-shaped mirrorextending in longitudinal direction and reflecting the radiation into afocus region, and an absorber line extending in longitudinal directionthrough the focus region of the trough-shaped mirror and having a guidetube for the heat transport medium and an absorber pipe surrounding theguide tube such that an annular chamber is formed between guide tube andabsorber line, with which the problems existing as a result of theuneven irradiation of the absorber line are also reduced or eliminated,it is suggested that an annular passage medium flow in the annularchamber and that the annular passage medium couple the guide tubethermally to the absorber pipe.

This patent does not solve the problem of enhancing heat transfer forthe internal surface of the guide tube.

US patent application No. 20100236239 describes a method for generatingsteam for a turbine electric power plant, which uses solar radiation.Solar radiation is directed onto a solar receiver. The solar receiverincludes a first section, which receives feedwater input and is arrangedto heat the feedwater input to generate steam using the directed solarradiation. Feedwater flows through a feedwater vessel to serve asfeedwater input to an inlet of the first section of the receiver. Wateris separated from the steam in a steam separation vessel, which is influid communication with an outlet of the first section of the receiver.The feedwater input may be selectively preheated by a source of preheatother than solar energy in response to system operating conditions,predicted insolation schedule, or an electrical energy tariff schedule.

We see that this patent application does not solve the problem of steamsuperheating.

US patent application No. 20110239651 discloses heat transfer pipes,which uniformly heat a compressible working fluid passing there throughwith a simplified supporting structure and reduced manufacturing costs.A solar central receiver on top of a tower on the ground includes heattransfer pipes arranged in the south-north direction; and a casingaccommodating the pipes and has a solar radiation inlet through whichsunlight reflected by heliostats on the ground is transmitted to thelower surface side of the pipes. The pipes are at equal intervals on asolar radiation receiving surface parallel to a heliostat field on whichthe collectors are, or inclined with respect to the heliostat field onwhich the collectors are, and the diameters of the pipes aresubstantially inversely proportional to the shortest distance from theinlet to the central axes of the respective pipes in the longitudinaldirection.

US patent No. 20090261591 application describes a solar power generationsystem, which includes a solar receiver disposed on a tower thatreceives radiant heat reflected from a field of solar collectors. Thesolar receiver includes an evaporator having a plurality of verticallyoriented tubes to form a panel for receiving a fluid, such as waterand/or steam, wherein the tubes have a rifled internal surface. Thefluid within the tubes has a mass flow greater than 0.2.times.10.sup.6lb/hr/ft.sup.3 at a pressure in the range of 100-2850 psia, whereinradiant heat fluxes on the outside of the tubes exceed 185,00but/hr/ft.sup.2.

The proposed rifled internal surface of the tubes does not provide arequired enhancement of the heat transfer coefficient for steamsuperheating.

US patent application No. 20080302314 describes a solar concentrationplant, which uses water/steam as a heat-carrying fluid; in anythermodynamic cycle or system for the exploitation of process heat,which is comprised of an evaporation subsystem, where saturated steam isproduced under the conditions of pressure of the system, and asuperheating subsystem through which the steam reaches the requiredconditions of pressure and temperature at the turbine inlet.

This patent application does not give any technical solution forenhancement of the heat transfer coefficient in the steam superheatingunit.

US patent application No. 20080078378 describes a solar tower centralreceiver with a separated boiler and a super-heater allowing bettercontrol on the output steam's temperature. The boiler takes higher solarflux density and works at lower temperature while the super-heater takeslower solar flux and works at high temperature to optimize the cost toperformance ratio. The boiler consists of parallel pipes as solarabsorber and the super-heater consists of helix parallel pipes as asolar absorber.

We see that this patent application does not give any technical solutionfor enhancement of the heat transfer coefficient in the steamsuperheating unit.

EP2372265 describes a thermal solar energy collector with a solarradiation absorption panel, inside which the heat-conducting fluidflows; this solar radiation absorption panel is situated inside aparallelepipedal box with an opening having a transparent cover at thefront; the rear wall of the box has a system of seals and reservoirs,which accommodate the expansion and contraction of vertical tubes of thepanel and horizontal connections by means of gentle changes in thecurvature of the tube bends and slight rotations of the reservoirs, withthe addition of a system for filling the box with an inert gas.

In addition, some patent application should be mentioned, such as WONos. 20111044281, 201103033, 2010132849, 2010093235, EP 2000669.

These patent applications do not give any technical solution forenhancement of the heat transfer in the steam superheating unit.

There are some US patents and patent applications, which are related toplate dish heat exchangers and their constructions somewhat resemble areceiver of solar concentrated radiation, which is proposed in thisinvention.

For example, U.S. Pat. Nos. 7,717,164, 7,533,717, 7,426,957, 6,546,996,5,927,394, 5,099,912, 4,892,136, 4,708,199, 4,561,494, US patentapplications Nos. 20030106679, 20070084809, German patents DE-A 43 14808, DE-A 195 11 991 or DE-A 197 50 748 are related to this technicalfield. However, these patents and patent applications describe heatexchangers intended to cool oil by a cooling liquid and they do notsuitable for heating a gaseous medium by concentrated solar radiation.

BRIEF SUMMARY OF THE INVENTION

This invention is based on possibility to achieve enhancement of heattransfer from a heat sourcing member to a gaseous heat transfer mediumflowing along it by extending the internal surface of the heat sourcingmember and by generation of multi jet flow between fins, which presentstructural units of this extended internal surface. It is known, thatapplication of multi-jet flow allows to obtain very high values of theNusselt number, i.e.—high values of the heat transfer coefficient. Forexample, the article: Dae Hee Lee et al. “Heat transfer enhancement bythe perforated plate installed between an impinging jet and the targetplate”; Int. Journal of Heat and Mass Transfer, 45 (2002) pp. 213-217describes this phenomena.

More specifically, this invention proposes a new method of an internalfinning of a solar radiation absorbing tube placed in the focal areas ofsolar radiation concentrating systems applying tracking trough parabolicmirrors or tracking one-curvature Fresnel mirrors. In addition, suchsolar radiation absorbing tubes may be used in solar concentratingsystems based on application of tracking heliostats, when concentratedsolar radiation is absorbed by a bank of solar radiation absorbingtubes, which are situated in a radiation receiving chamber (STP system).

The outer surface of the solar radiation absorbing tube (or tubes in thecase of STP system), which is provided preferably with an outerselective radiation absorbing coating, plays a role of theabovementioned heat source member.

An extended heat transferring structure according to this invention isformed by stacked metal perforated plates, preferably, of the circularshape; each metal perforated plate is provided with an inclined rim oran upright two-step rim.

In the case of usage of the upright two-step rim, the difference betweenthe outer radii of both steps of the rim approximates that of the rimwidth. The adjacent metal perforated plates in their stacked assemblyare sealingly jointed by brazing or welding.

The perforations of the metal plates can be executed by differenttechnological methods; for example, by piercing or scrapless piercing,drilling, punching, photochemical milling and electroforming. Theperforations in the metal plates can be of the circular shape, the ovalshape, the slot shape etc.

In addition, the adjacent circular metal plates may be mutually turnedthrough a certain angle in such a way that the axes of perforations ofone circular metal plate intersect the bridges of the adjacent metalcircular plates.

In order to achieve higher stiffness of the obtained tubular piece, aset of metal longitudinal rods can be joined with it by brazing orwelding.

The external surface of the obtained tubular unit is covered with asolar radiation absorbing coating. This coating has preferably selectiveoptical characteristics.

In such a way, a solar radiation receiver for PTC and LFR systemscomprises:

-   -   a radiation receiving metal pipe, which has at least one section        constructed from circular perforated plates with inclined rims        or upright two-step rims; these circular perforated plates are        stacked and sealingly joined by welding or brazing (diffusion        welding may be used as well for their joining);    -   another section of the radiation receiving metal pipe is a        common metal pipe, which is joined by brazing or welding with        the aforementioned section formed from the stacked circular        perforated plates;    -   two fittings joined with the free ends of these pipe sections;    -   a selective absorptive coating covering the outer surfaces of        the first and second pipe sections;    -   two metal bellows, which are joined with the fittings;    -   a glass envelope, which is joined at its ends with two metal        bellows by two glass-to-metal sealings; this glass envelope is        provided with an evacuating nozzle for vacuum creation between        the radiation receiving metal pipe and the glass envelope.

In such a way, the second section of the radiation receiving metal pipeserves for heating and evaporation of the most fraction of thefeedwater, and the first section formed from the stacked perforatedplates serves mainly for superheating the saturated steam obtained inthe second section.

It should be noted, that the stacked perforated plates of the secondsection play a role of a demister.

In the case of application of solar collectors of PTC and LFR types forsuperheating steam or heating a gaseous heat transfer medium (forexample, the air), the metal pipes of their solar radiation receiversconsist of only the first type sections formed by stacking and joiningthe perforated circular plates with their rims, as it has been describedpreviously.

In the case of a central receiver mounted on a tower (STP) with an arrayof tracking heliostats, which reflect solar radiation on this centralreceiver, this central receiver comprises a radiation receiving chamberwith at least one glazed aperture intended for entering concentratedsolar radiation into the internal space of the radiation receivingchamber.

The internal space of the radiation receiving chamber consists of one ormore rows of parallel metal radiation receiving pipes, wherein eachmetal radiation receiving pipe has a first section manufactured fromstacked perforated metal plates with inclined or upright two-step rims;these stacked perforated metal plates are sealingly joined by brazing orwelding.

A second section of each metal radiation receiving pipe is a commonmetal pipe, which is joined by brazing or welding with the first sectionformed from the stacked perforated plates; two fittings are joined withthe free ends of each pair of the first and second pipe sections. Thefree ends of the fittings are joined with metal bellows.

There are lower and upper headers; the lower header serves for intake offeedwater from an outside delivery unit and its distributing through thebellows and their fittings into the second sections of the metalradiation receiving pipes; the upper header serves for intake of thesuperheated steam from the first section of the metal radiationreceiving tubes and its delivery to an outside consumer.

Selective absorptive coatings cover the outer surfaces of the first andsecond pipe sections of the metal radiation receiving pipes. It shouldbe noted that these selective absorptive coatings can cover only theouter areas of the first and second pipe sections, which are radiated byconcentrated solar radiation.

In the case of application of a solar collectors of STP type forsuperheating steam or heating a gaseous heat transfer medium (forexample, the air), the radiation receiving metal pipes situated in theradiation receiving chamber consist of only the first type tubularsections formed from stacking the perforated circular plates with theirrims, as it has been described previously.

It should be noted, that the proposed pipes formed from the stackedmetal plates may be applied in radiant or combine superheating units ofsteam generators operating by combustion of gaseous, liquid or solidfuel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a and FIG. 1 b show a front view and a cross-section A-A of aperforated metal plate with circular perforations and an inclined rim.

FIG. 1 c and FIG. 1 d show a front view and a cross-section B-B of aperforated metal plate with its upright two-step rim and circularperforations.

FIG. 2 a and FIG. 2 b show a front view and a cross-section A-A of aperforated metal plate with its upright two-step rim and circularnipple-wise perforations formed by scrapless piercing.

FIG. 3 a and FIG. 3 b show a front view and a cross-section A-A of aperforated metal plate with its inclined rim and sharp-leaved openings.

FIG. 3 c and FIG. 3 d show a front view and a cross-section B-B of aperforated metal plate with its upright two-step rim and sharp-leavedopenings.

FIG. 4 a and FIG. 4 b show front views of two perforated metal plateswith their upright two-step rims and differently oriented centralrectangular openings allowing angular shifting of the adjacentperforated metal plates in the process of their stacking.

FIG. 5 a and FIG. 5 b show two tubular units 500 and 501 fabricated fromstacked and joined perforated plates with inclined rims and uprighttwo-step rims.

FIG. 6 shows an axial cross-section of a solar radiation receiver forPTC and LFR systems; this solar radiation receiver comprises a commonmetal tubular section and another tubular metal section formed fromstacked perforated circular plates.

FIG. 7 a, FIG. 7 b and FIG. 7 c show: a cross-sectional view of aradiation receiving chamber of a solar tower power station (STP);semi-sectional views of the lower and upper sections of a bank of solarradiation absorbing pipes installed in this radiation receiving chamber.

FIG. 7 d, FIG. 7 e and FIG. 7 f show a cross-section view A-A of theradiation receiving chamber of the solar tower power station (STP),which is demonstrated in FIG. 7 a, lower and upper detail sections I andII of the bank of the solar radiation absorbing pipes installed in thisradiation receiving chamber.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 a and FIG. 1 b show a front view and a cross-section A-A of aperforated metal plate 100 with circular perforations and an inclinedrim.

The perforated metal circular plate 100 comprises a flat member 101,circular perforations 102 and an inclined rim 103.

FIG. 1 c and FIG. 1 d show a front view and a cross-section B-B of aperforated plate 104 with its upright two-step rim and circularperforations.

The perforated circular metal plate 104 comprises a flat member 105,circular perforations 106 and an upright two-step rim with its lower andupper sections 108 and 107.

FIG. 2 a and FIG. 2 b show a front view and a cross-section A-A of aperforated metal plate 200 with its inclined rim and circularnipple-wise perforations formed by scrapless piercing.

The perforated circular plate 200 comprises a flat member 201; circularperforations 202 terminated on one side with nipples 204 and an inclinedrim 203, which is oriented in the same direction as nipples 204.

FIG. 3 a and FIG. 3 b show a front view and a cross-section A-A of aperforated metal plate with its inclined rim and sharp-leaved openings.

The perforated metal circular plate 300 comprises a flat member 301,sharp-leaved perforations 302 and an inclined rim 303.

FIG. 3 c and FIG. 3 d show a front view and a cross-section B-B of aperforated metal plate with its upright two-step rim and sharp-leavedopenings.

The perforated circular metal plate 304 comprises a flat member 305,sharp-leaved perforations 306 and an upright two-step rim with its lowerand upper sections 308 and 307.

FIG. 4 a and FIG. 4 b show front views of two perforated plates withtheir inclined rims and differently oriented central rectangularopenings allowing angular shifting of the adjacent perforated plates inthe process of their stacking.

The perforated circular metal plate 400 comprises a flat member 401,circular perforations 402, an inclined rim 403 and a central rectangularopening 404.

The perforated circular metal plate 405 comprises a flat member 406,circular perforations 407, an inclined rim 408 and a central rectangularopening 409, which is angularly shifted with respect to the othercircular openings in comparison with the perforated circular metal plate400.

FIG. 5 a and FIG. 5 b show two tubular units 500 and 501 fabricated fromstacked and joined perforated plates with inclined rims and uprighttwo-step rims.

FIG. 5 a demonstrates flat circular plates 502 with sharp-leavedperforations 507, inclined rims 503, fitting 504, fitting 505 and welds506.

FIG. 5 b demonstrates flat circular plates 508 with sharp-leavedperforations 511, lower sections 510 and upper sections 509 of uprighttwo-step rims, fitting 512, fitting 513 and welds 514.

FIG. 6 shows an axial cross-section of a solar radiation receiver forPTC and LFR systems; this solar radiation receiver comprises a commonmetal tubular section, which is joined with another tubular metalsection constructed from stacked perforated circular plates.

The solar radiation receiver 600 comprises:

-   -   a first metal tubular section 601 intended for heating and        evaporation of water with obtaining saturated steam;    -   a second metal tubular section, which consists of stacked        circular plates 602 with upright two-step rims 603 and        sharp-leaved perforations 606; this second metal tubular section        is intended for steam superheating;    -   fittings 604 and 610;    -   bellows 605;    -   a transparent glass envelope 609;    -   welds 607 for joining the upright two-step rims 603, the first        metal tubular section 601, fittings 604 and 610;    -   glass-to-metal seals 608 for joining bellows 605 with        transparent glass envelope 609;    -   an evacuation nozzle 611.

FIG. 7 a, FIG. 7 b and FIG. 7 c show: a cross-sectional view of aradiation receiving chamber 700 of a solar tower power station (STP);semi-sectional views of the lower and upper sections of a bank of solarradiation absorbing pipes installed in this radiation receiving chamber.

The radiation receiving chamber 700, which is installed on tower 703,comprises:

-   -   a chamber housing 701 with a thermal insulation 702 and glazing        704 of the front wall of the chamber housing 701;    -   an upper header 706 and a lower header 708;    -   an inlet line 705, which supplies water into the lower header        708, and an outlet line 714, which serves for discharging        superheated steam from the upper header 706;    -   elbow pipes 709 and 710, which are in fluid communication with        the upper and lower headers 706 and 708;    -   bellows 707 and 712;    -   common metal absorbing pipes 711 with selective absorbing        coatings; these selective absorbing coatings cover at least the        areas of these common metal absorbing pipes 711, which are faced        to glazing 704;    -   metal radiation absorbing pipes 713 with selective absorbing        coatings; these selective absorbing coatings cover at least the        areas of the metal radiation absorbing pipes 713, which are        faced to glazing 704; these metal absorbing pipes 713 are        constructed from stacked metal plates provided with rims; the        rims of adjacent plates are sealingly joined.

FIG. 7 d, FIG. 7 e and FIG. 7 f show a cross-section view A-A of theradiation receiving chamber of the solar tower power station (STP),which is demonstrated in FIG. 7 a, lower and upper detail sections I andII of the bank of the solar radiation absorbing tubes installed in thisradiation receiving chamber. The radiation receiving chamber 700, whichis installed on tower 703, comprises:

-   -   a chamber housing 701 with a thermal insulation 702 and glazing        704 of the front wall of the chamber housing 701;    -   an upper header 706 and a lower header 708;    -   an inlet line 705, which supplies water into the lower header        708, and an outlet line 714, which is discharging superheated        steam from the upper header 706;    -   elbow pipes 709 and 710, which are in fluid communication with        the upper and lower headers 706 and 708;    -   bellows 707 and 712;    -   common metal absorbing pipes 711 with selective absorbing        coatings; these selective absorbing coatings cover at least the        areas of these common metal absorbing pipes 711, which are faced        to the glazing;    -   metal radiation absorbing pipes 713 with selective absorbing        coatings; these selective absorbing coatings cover at least the        areas of the metal radiation absorbing pipes 713, which are        faced to the glazing; these metal absorbing pipes 713 are        constructed from stacked metal plates provided with rims; the        rims of adjacent plates are sealingly joined.

1. A radiation absorbing metal pipe intended for heating gaseous mediumor gaseous-liquid mixture; said radiation absorbing metal pipe isconstructed from stacked metal flat plates with perforations andinclined rims; said inclined rims of said stacked metal flat plates aresealingly joined by welding or brazing; the ends of the tubular unitfabricated from said stacked metal flat plates are sealingly joined withfittings; the external surfaces of said tubular unit and said fittingsare covered with a radiation absorbing coating.
 2. The radiationabsorbing metal pipe intended for heating gaseous medium orgaseous-liquid mixture as claimed in claim 1, wherein the metal flatplates are provided with upright two-step rims.
 3. The radiationabsorbing metal pipe intended for heating gaseous medium orgaseous-liquid mixture as claimed in claim 1, wherein the differencebetween the outer radii of both steps of the upright rim approximatesthat of said rim width.
 4. The radiation absorbing metal pipe intendedfor heating gaseous medium or gaseous-liquid mixture as claimed in claim1, wherein the metal flat plates have the circular shape.
 5. Theradiation absorbing metal pipe intended for heating gaseous medium orgaseous-liquid mixture as claimed in claim 1, wherein the metal flatplates have the oval shape.
 6. The radiation absorbing metal pipeintended for heating gaseous medium or gaseous-liquid mixture as claimedin claim 1, wherein the metal flat plates have the rectangular shape. 7.The radiation absorbing metal pipe intended for heating gaseous mediumor gaseous-liquid mixture as claimed in claim 1, wherein theperforations are shaped as openings with nipples.
 8. The radiationabsorbing metal pipe intended for heating gaseous medium orgaseous-liquid mixture as claimed in claim 1, wherein the perforatedmetal plates are provided with differently oriented central openings ofsuch shape, which allows angular shifting of said adjacent perforatedmetal plates in the process of their stacking.
 9. The radiationabsorbing metal pipe intended for heating gaseous medium orgaseous-liquid mixture as claimed in claim 1, wherein the radiationabsorbing coating has selective radiation absorbing features.
 10. Theradiation absorbing metal pipe intended for heating gaseous medium orgaseous-liquid mixture as claimed in claim 1, wherein said radiationabsorbing metal pipe comprises two sealingly joined units: the first oneis a common metal pipe and the second one is constructed from thesealingly joined stacked flat metal plates provided with theperforations.
 11. The radiation absorbing metal pipe intended forheating gaseous medium or gaseous-liquid mixture as claimed in claim 1,wherein there are metal longitudinal rods, which are joined by brazingor welding with the outer surface of the tubular unit constructed fromthe stacked metal flat plates; said rods likewise are covered with theradiation absorbing coating.
 12. A solar radiation receiver for a solarthermal collector constructed in the form of a parabolic trough (PTC) orthe solar thermal collector constructed with application of linearFresnel reflectors (LFR); said solar radiation receiver comprises: aradiation absorbing metal pipe constructed as it is described in claim1; metal bellows, which are joined with two fittings of said radiationabsorbing metal pipe; a glass envelope, which is joined at its ends withsaid two metal bellows by two glass-to-metal sealings; said glassenvelope is provided with an evacuating nozzle for vacuum creationbetween said radiation absorbing metal pipe and said glass envelope. 13.The solar radiation receiver for a solar thermal collector constructedin the form of a parabolic trough (PTC), or the solar thermal collectorconstructed with application of linear Fresnel reflectors (LFR) asclaimed in claim 12, wherein the radiation absorbing metal pipecomprises some sealingly joined units: a common metal pipe; the tubularunit assembled from the sealingly joined stacked plates provided withthe perforations; fittings, which are joined with the free ends of saidcommon pipe and said tubular unit.
 14. A solar radiation receiver for asolar thermal station with an array of tracking reflectors, wherein saidsolar radiation receiver is mounted on a tower (STP); said solarradiation receiver is constructed as a radiation receiving chamber withat least one glazed aperture intended for entering concentrated solarradiation from said tracking reflectors into the internal space of saidradiation receiving chamber, wherein the internal space of saidradiation receiving chamber consists of one or more rows of parallelradiation absorbing metal pipes; each said radiation absorbing metalpipe is constructed as it is claimed in claim 1; the free ends of thefittings of said radiation absorbing metal pipe are joined with metalbellows; there are lower and upper headers, which are situated in saidradiation receiving chamber and they are in fluid communication throughsaid metal bellows with said radiation absorbing metal pipes.
 15. Thesolar radiation receiver for a solar thermal station with an array oftracking reflectors, wherein said solar radiation receiver is mounted ona tower (STP); said solar radiation receiver is constructed in the formof a radiation receiving chamber as it is claimed in claim 14, whereineach radiation absorbing metal pipe comprises several sealingly joinedunits: a common metal pipe and a tubular unit assembled from thesealingly joined stacked flat metal plates provided with theperforations; fittings, which are joined with the free ends of saidcommon pipe and said tubular unit.
 16. The solar radiation receiver fora solar thermal station with an array of tracking reflectors, whereinsaid solar radiation receiver is mounted on a tower (STP) as claimed inclaim 14; said solar radiation receiver is applied for carrying outthermo-chemical reactions in a gaseous medium flowing in it.
 17. Thesolar radiation receiver for a solar thermal power station with an arrayof tracking reflectors, wherein said solar radiation receiver is mountedon a tower (STP) as claimed in claim 14; said solar radiation receiveris applied for heating the pressurized air.
 18. The solar radiationreceiver for a solar thermal power station with an array of trackingreflectors as it is claimed in claim 14, wherein the solar radiationreceiver is mounted on the ground.